Enhanced spin accumulation and novel magnetotransport in nanoparticles
Enhanced spin accumulation and novel magnetotransport in nanoparticles
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DOI：
10.1038/nmat1278
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发表时间：
2004-12
期刊：
影响因子：
41.2
通讯作者：
K. Yakushiji;F. Ernult;H. Imamura;K. Yamane;S. Mitani;K. Takanashi;S. Takahashi;S. Maekawa;H. Fujimori
中科院分区：
文献类型：
--
作者：
K. Yakushiji;F. Ernult;H. Imamura;K. Yamane;S. Mitani;K. Takanashi;S. Takahashi;S. Maekawa;H. Fujimori
自旋注入和积累是支持自旋电子器件的各种概念的关键现象。由于其离散的能级和大的充电能量，这些现象预计在纳米颗粒中比块状结构得到增强。在本文中，通过制备适当的含有钴纳米颗粒的微加工器件，在单电子隧道机制中进行精确的磁输运测量。在这里，我们提供了磁性纳米粒子中自旋积累特征的实验证据，例如磁阻的振荡，其周期性符号变化是偏置电压的函数。磁阻行为的理论分析清楚地表明，与本体相比，纳米颗粒中的自旋弛豫时间大大增强。
Spin injection and accumulation are key phenomena supporting a variety of concepts for spin-electronic devices. These phenomena are expected to be enhanced in nanoparticles over bulk structures due to their discrete energy levels and large charging energies. In this article, precise magnetotransport measurements in the single-electron tunnelling regime are performed by preparing appropriate microfabricated devices containing cobalt nanoparticles. Here we provide experimental evidence for characteristic features of spin accumulation in magnetic nanoparticles, such as oscillations of the magnetoresistance with a periodical sign change as a function of bias voltage. Theoretical analysis of the magnetoresistance behaviour clearly shows that the spin-relaxation time in nanoparticles is highly enhanced in comparison with that in the bulk.